It is known to employ a spark ignited pre-combustion chamber assembly (in the following referred to as “pre-chamber assembly) including a pre-combustion chamber (in the following referred to as “pre-chamber”) in some internal combustion engine applications, such as gaseous fuel applications. Typically, a pre-chamber is a relatively small gas accumulating chamber located in the pre-chamber assembly or in the engine cylinder head. The pre-chamber is in fluid communication with the main combustion chamber of the internal combustion engine via a number of small flow channels. During operation, an ignition electrode generates a spark for igniting a mixture of gaseous fuel and air within the pre-chamber (as opposed to igniting the gaseous fuel in the main combustion chamber). Ignition of the gaseous fuel in the pre-chamber generates a front of burning fuel which is jetted or otherwise advanced through the flow channels into the main combustion chamber thereby igniting the mixture of gaseous fuel and air therein.
It is further known to provide the ignition electrode in a crucial shape. In such case, the ignition electrode may include a plurality of electrode arms extending substantially upright from a connecting section into the interior of the pre-chamber.
In the prior art, the manufacturing process of the ignition electrode may include some mechanical manufacturing steps including, for example, cutting a crucial piece out of a metal sheet, bending each electrode arms into the desired shape, and applying a metal coat, such as, for instance, an iridium coat to the bended ignition electrode. However, the mechanical bending process may be limited due to, for example, the material's yield strength and, during operation of the ignition electrode, the electrode arms may break as the bending radius were selected too small for the used material and used material thickness.
US 2014/0196684 A1 discloses a spark plug for an internal combustion engine, in particular a gas engine. The spark plug includes a center electrode and at least one earth electrode group, each comprising one or more earth electrode platelets. The center electrode includes at least one center electrode platelet having a center electrode surface, and the center electrode surface is inclined in a range from 0° to 50°, preferably at most 45°, to a cross-sectional plane transverse to the longitudinal axis of the spark plug. Each earth electrode platelet of an earth electrode group has an earth electrode surface facing towards the center electrode surface, spaced apart from the earth electrode surface and running substantially parallel to the earth electrode surface.
A pre-chambered type spark plug with pre-chamber entirely below a bottom surface of a cylinder head is known from US 2005/0211217 A1.
The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of prior systems.